Elixir files

Elixir uses two files, .ex for compiled code and .exs for scripts. They must both be UTF-8 encoded. We will go over .ex some more when we introduce mix in the next chapter. But for now, let's discuss .exs a little more.

We can write all the Elixir code we have shown so far into a script (we won't though, there is just a small subset) and then we can use the interactive interpreter to load up our script and run it.

For example, we can put the MyMap code from earlier into a script:

defmodule MyMap do
  def map([], _) do
    []
  end

  def map([h|t], f) do
    [f.(h) | map(t, f)]
  end
end

square = fn x -> x * x end
MyMap.map([1, 2, 3, 4, 5], square)

Go ahead and save it as mymap.exs. Launch a terminal and use the cd command to navigate to the directory that you saved your script in and then launch iex.

Once in iex, we will use import_file/1 to import and launch our script.

In your iex, type h(import_file/1) to get the documentation of import_file/1:

iex(1)> h(import_file...